Electronic printing device comprising an array of tunnel cathodes

ABSTRACT

A solid-state electronic printing device which is compact and does not require the use of a high voltage, wherein the movement of electrons emitted into the atmosphere from a tunnel cathode or a photo-cathode is controlled by the potential of a control electrode disposed in the vicinity of said cathode, thereby said electrons being deposited, directly or in the form of a corresponding amount of ink, on a recording medium according to said potential of said control electrode.

15] 3,653,063 51 Mar. 28, 197 2 United States Patent Miyazaki v m BH 578 666 wow NW 237 Wynn 4 8 5 000 333 L E Em CU T F Y G mm TR mA RN PA CG I NNS mmm R0 P H EMT L O A ECC 4 5 3,480,962 11/1969 Weigl et al..

[72] Inventor: Ellchi Mlyazaki, Tokyo, Japan 2,297,398 9/1942 Fries......... 3,438,053 4/1969 Howell....... 3,424,862 1/1969 346/74 ES Berthold...............,............346/74 CR [73] Assignee: Matsushlta Electric Industrial Co., Ltd.,

Osaka, Japan [22] Filed: 1968 Primary ExaminerBernard Konick [21] Appl. No.2 785,633

Assistant Examiner-Gary M. Hoffman Attorney-Stevens, Davis, Miller and Mosher ABSTRACT Foreign Application Priority Data 534 6 236 H0 111 6 333 1 m WdRS mm 4M J6 m m w s m m u E u u m 4 m.m F "u" mm4 "u" a nu/ "u" 6 "n" 4 mmm "m3 mma PD-D. m aaa 1]] m n 777 666 mnr 999 8 111 -e, 8 8 8 222 a m eec M 666 SMR DDD UIF nuo o g device which is compact and does not require the use of a high voltage, wherein the movement of electrons emitted into the atmosphere from a tunnel cathode or a photo-cathode is controlled by the potential of a control electrode disposed in the vicinity of said cathode, thereby said electrons being deposited, directly or in the form a corresponding amount of ink, on a recording medium according to said potential of said control electrode.

References Cited UNITED STATES PATENTS 4 Claims, 4 Drawing Figures 3'118'050 ail???71:21:317312""" 71 .n

PATENTEDMARZB I972 SHEET 2 OF 2 FIG. 3

l l'l 14 V INVENTOR 51/4/11 ily 92pm ATTORNEYS ELECTRONIC PRINTING DEVICE COMPRISING AN ARRAY F TUNNEL CATHODES This invention relates to an electronic printing device, particularly to a solid-state electronic printing device for reproducing a record from a received electric information signal.

For a conventional electronic printing system in which an image quantized by scanning at the sending end is transmitted as asequential electric signal and recomposed into the image on a recording medium at the receiving end, various types of electronic printing tubes based on cathode-ray tubes are generally used. However, these printing tubes have not a few disadvantages. For example, such tubes are usually large, especially in length. Further, the use of a high voltage is required in operating such a device.

The above disadvantages are eliminated with the printing device of this invention.

The printing device according to this invention comprises an array of electron emissive cells, a control electrode disposed in front of said array of electron emissive cells for controlling the electrons emitted from said cells according to the signal voltage, and means for producing a record on a recording medium according to the amount of said electrons.

The objects and features of this invention will be clarified by the following description pertaining to embodiments of this invention and with reference to the accompanying drawings, in which, but omitting DC voltage sources for the sake of simplicity; I

FIG. 1 is a schematic sectional view of the photoelectric emissive cathode in an embodiment of this invention, also showing a part of electric connections;

FIGS. 2, 3 and 4 are schematic sectional views of different embodiments of this invention, including schematic electric connection diagrams. I

The embodiment shown in FIGS. 1 and 2 relates to a printing device in which photo-electrons emitted from a gold film irradiated with ultraviolet rays in the atmosphere are caused to scan a recording medium and are modulated with the image signal at the same time, the electrons being thereby adsorbed in the recording medium according to the image signal.

In FIGS. 1 and 2, an array of cellular gold films 2 is vapourdeposited on an ultraviolet ray pervious substrate 1 such as a quartz substrate. Photo-electrons are emitted from the surface of said thin gold film 2 by constantly irradiating ultraviolet rays from a source 7 on said thin gold film 2. An electrode 4 interposed between insulators 3, 3' is provided in each of the spaces between said thin gold films 2. The signal voltages from signal source are sequentially applied to each electrode 4 through a switch S which operates in synchronization with the signal, thus effecting a pulse scanning.

The flow of electrons emitted from the gold film 2 is modulated with the potential of the electrode 4 and is drawn toward the back electrode 6. Thus, electrons of an amount corresponding to the signal voltage at the instant are deposited on a recording paper 5, thereby an electronic recording being effected. The other components shown in FIG. 2 are a bias voltage source 8 for determining an operating point of the device like a grid bias for a triode and a voltage source 9 for accelerating a modulated electron fiow like the plate voltage source of a triode.

As described above, a very effective printing device which is simple, compact and does not require a vacuum apparatus, is obtained according to this invention.

FIG. 3 shows another embodiment of this invention, in which reference numeral 11 designates a dielectric substrate, 12 a thin metal film such as an aluminum film, 13 a thin insulating layer, for example, of aluminum oxide, and 14 cellular thin films of a metal such as gold. A voltage applied between both metal films l2 and 14 yields a very intense electric field across the insulating film 13, because said insulating film is very thin. The thus yielded intense electric field pulls out electrons from the metal film 12 by the tunnel effect. The extracted electrons are emitted through the insulating layer 13 and the thin metal film 14. The value of the voltage applied between both metal films 12 and I4 is ordinarily of the order of 10 volts. In short, the above-described assembly consisting of the insulating substrate 11, the metal film 12, insulating layer 13 and the second metal film 14, constitutes a tunnel cathode 15. In front of this tunnel cathode 15 is provided a control electrode 17 interposed between insulators l6 and 16'. The signal voltage is applied to said control electrode 17.

The flow of electrons emitted from said tunnel cathode 15 is modulated with the voltage of the control electrode 17 and is drawn toward the back electrode 19. Thus, an amount of electrons corresponding to the value of the signal voltage at the instant are deposited on a sheet of recording paper 18 placed before the back electrode 19, whereby an electronic recording is effected. The other components shown in FIG. 3 are a voltage source 20 for the tunnel cathode 15, a bias voltage source 7 21, a voltage source 22 for electron acceleration, and the signal source 23. The bias voltage source 21 is identical with the bias voltage source 8 in FIG. 2 and functions like a grid bias voltage source for a triode. The voltage source 20 cooperates with the bias voltage source 21 to provide the electric field strength of i0 v./cm. between the metal film l2 and the second metal films 14 of the tunnel cathode 15, thereby drawing out electrons into the external atmosphere through the second metal films 14. The voltage source 22 functions in the same way as the voltage source 9 in FIG. 2.

As described above, according to this embodiment, a compact and simple-structured printing device is obtained utilizing an array of cellular tunnel cathodes, a control electrode being provided in front of said tunnel cathode, said tunnel cathodes being scanned in synchronization with the signal which is applied to said control electrode, and thus electrons being adsorbed on the recording medium according to said signal.

FIG. 4 shows still another embodiment of this invention, in which an array of cellular tunnel cathodes are sequentially scanned by pulse scanning to let them emit electrons sequentially, the emitted electrons electrifying ink disposed in front of and adjacent to said cathodes, the amount of the electrification of said ink being controlled by the potential of the control electrode, and thus the ink being deposited on a sheet of ordinary paper at a rate depending on the signal voltage.

Referring to FIG. 4, an ink vessel which is provided with an array of small through-holes at positions aligned with metal films 34' of said tunnel cathode 35, is disposed in front of a tunnel cathode 35. Numeral 31 designates a dielectric substrate, 32 a metal film and 33 an insulating layer. Further, in front of said ink vessel is disposed a control electrode 39 interposed between insulators 38 and 38', the signal voltage being applied to said control electrode 39.

Electrons emitted from the tunnel cathode 35 electrifies printing ink 37 contained in said ink vessel, and particles of the electrified 'ink are drawn out from the ink vessel according to the signal voltage applied to said control electrode 39 and are accelerated by the high potential of a back electrode 41. Thus, the amount of ink corresponding to the signal voltage at the instant is transferred to a sheet of paper 40 placed in front of the back electrode 41, whereby a printing is performed. The other components shown in FIG. 4 include a voltage source 42 for the tunnel cathode, a bias voltage source 43, a voltage source 44 for the acceleration of electrons, and the signal source 45. The voltage source 42, the bias voltage source 43 and the voltage source 44 correspond respectively to the voltage source 20, the bias voltage source 21 and the voltage source 22 in FIG. 3, the former functioning in the same way as the latter.

As described above, according to this embodiment, an ink vessel which has an array of through-holes in alignment with an array of tunnel cathodes is disposed in front of said tunnel cathodes and a control electrode is disposed further in front of said ink vessel, the signal voltage being applied to said control electrode and said array of tunnel cathodes being scanned in synchronization with the signal, thus an electrostatic printing being performed on a sheet of ordinary paper with a compact and simple-structured device.

What we claim is:

1. An electronic printing device for producing a record corresponding to an applied signal voltage comprising an array of tunnel cathodes, means for scanning said array of tunnel cathodes, means for producing a' record on a recording medium by electrons emitted by said cathodes which directly impinge upon said recording medium, and a control electrode interposed between said array of tunnel cathodes and said recording medium, said control electrode controlling the electrons emitted from said cathodes in accordance with said signal voltage.

2. An electronic printing device as defined in claim 1, which further comprises an ink vessel disposed between said array of electron emissive cells and said control electrode and adjacent to said electron emissive cells, said ink vessel being provided with small through-holes in alignment with said electron emissive cells, thereby to control the amount of ink transferred to a recording medium according to said signal voltage.

3. -An electronic printing device as defined in claim 1, wherein said array of electron emissive cells comprises an ultraviolet ray pervious substrate and an array of cells of thin gold film provided on said substrate.

4. An electronic printing device as defined in claim 1, wherein each of said electron emissive cells comprises a photo-electron emissive thin film and said control electrode consists of mutually discrete portions, each portion being disposed opposite to each of said electron emissive cells and said device further comprises means for switching said signal voltage sequentially over said discrete portions of said control electrode.

a a s s 

1. An electronic printing device for producing a record corresponding to an applied signal voltage comprising an array of tunnel cathodes, means for scanning said array of tunnel cathodes, means for producing a record on a recording medium by electrons emitted by said cathodes which directly impinge upon said recording medium, and a control electrode interposed between said array of tunnel cathodes and said recording medium, said control electrode controlling the electrons emitted from said cathodes in accordance with said signal voltage.
 2. An electronic printing device as defined in claim 1, which further comprises an ink vessel disposed between said array of electron emissive cells and said control electrode and adjacent to said electron emissive cells, said ink vessel being provided with small through-holes in alignment with said electron emissive cells, thereby to control the amount of ink transferred to a recording medium according to said signal voltage.
 3. An electronic printing device as defined in claim 1, wherein said array of electron emissive cells comprises an ultraviolet ray pervious substrate and an array of cells of thin gold film provided on said substrate.
 4. An electronic printing device as defined in claim 1, wherein each of said electron emissive cells comprises a photo-electron emissive thin film and said control electrode consists of mutually discrete portions, each portion being disposed opposite to each of said electron emissive cells and said device further comprises means for switching said signal voltage sequentially over said discrete portions of said control electrode. 